We need to buy a few hundred slotted weights, but these prices are
prohibitive. Anyone got any experience with an alternate source. Out of
frustration I have actually manufactured batches of 10g and 20g weights, but
there should be a better way.

I have my large plasma sphere out for some upcoming Halloween demos. Kids
are amazed by this device. One asked why the glowing purple lines (between
the central electrode and the outer glass surface) always rise. I never
really noticed this before, so I examined the motion for a while and it
was true. I was and remain baffled.